1. Field of the Invention
The present invention relates to a magnetic head suspension for supporting a magnetic head slider that reads and/or writes data from and to a recording medium such as a hard disk drive.
2. Related Art
Increase in capacity of a magnetic disk device requires improvement in accuracy for positioning a magnetic head slider on a target track. In this regard, there has been proposed a magnetic head suspension that enables coarse motion of a magnetic head slider in a seek direction by a main actuator such as a voice coil motor as well as micro motion of the magnetic head slider in the seek direction by a piezoelectric element functioning as a sub actuator.
For example, Japanese Unexamined Patent Application Publication No. 2009-080915 (hereinafter referred to as prior art document) proposes a magnetic head suspension with the piezoelectric element configured so that supply of a voltage to the piezoelectric element is made with use of a conductor layer of a flexure part.
More specifically, the magnetic head suspension disclosed by the prior art document includes a load bending part that generates a load for pressing the magnetic head slider toward a disk surface, a load beam part that transmits the load to the magnetic head slider, a supporting part that supports the load beam part via the load bending part and is swung about a swing center directly or indirectly by a main actuator, a flexure part that is supported by the load beam part and the supporting part while supporting the magnetic head slider, and paired right and left piezoelectric elements that are attached to the supporting part.
The supporting part is provided with a proximal end section that is connected directly or indirectly to the main actuator, a distal end section to which the load bending part is connected, an open section that is positioned between the proximal end section and the distal end section in a suspension longitudinal direction, and paired right and left connecting beams that are positioned on both sides of the open section in a suspension width direction and connect the proximal end section and the distal end section.
The piezoelectric element includes a piezoelectric a piezoelectric main body, and an upper electrode layer and a lower electrode layer that face to each other with the piezoelectric main body being interposed between them. The piezoelectric element has a distal end and a proximal end fixed to the distal end section and the proximal end section, respectively, by insulative adhesive agents, in a state where the lower electrode layer faces the disk surface.
The flexure part includes a flexure metal plate fixed to disk-facing surfaces of the load beam part and the supporting part by welding or the like, an insulating layer laminated on a disk-facing surface of the flexure metal plate, and the conductor layer laminated on a disk-facing surface of the insulating layer.
The conductor layer includes a signal wiring that is electrically connected to the magnetic head slider, and a voltage supply wiring for supplying a voltage to the piezoelectric elements.
The voltage supply wiring includes a laminated region that is laminated on the disk-facing surface of the insulating layer and an extending region that extends outward from the laminated region so as to face the lower electrode layer of the piezoelectric element. The extending region is electrically connected to the lower electrode layer through a lower conductive adhesive agent.
The upper electrode layer of the piezoelectric element is electrically connected through an upper conductive adhesive agent to an upper surface (a surface positioned on an opposite side from the disk surface) of the distal end section of the supporting part to have a ground potential.
The conventional magnetic head suspension with the above explained configuration is useful in that the supply of the voltage to the piezoelectric elements can be made without any additional elements being substantially required. However, since the lower conductive adhesive agent is exposed outward, there is a problem that filler particles such as Ag particles, which are included in the lower conductive adhesive agent, are likely to fall onto the disk surface. The filler particles, which have been fallen onto the disk surface, may damage the disk surface and the magnetic head slider.